Water ski bindings typically comprise a flexible, soft, natural or artificial rubber piece (which is customarily referred to as the binding rubber) which is constrained by a rigid, separately formed framework to pucker up and thereby form a pocket for receiving a portion of the skier's foot, such as the skier's forefoot in the case of a front binding or the skier's heel in the case of a heel piece binding or heel cup, as it is also called. The binding rubber is conventionally clamped between the rigid framework and the ski and is fastened in place usually by screws which extend through holes in the framework and the binding rubber. It is expressly understood that the binding rubber mentioned above is a flexible part which, unless otherwise indicated, may be made from natural rubber or a plastic or artificial material.
Due to the substantial pressure applied to the binding rubber by the skier while skiing, the binding rubber tends to be pulled away from the framework and fastening screws, causing the binding rubber to tear and therefore fail in the region of some of the screw holes. For a front or toe piece binding, the failure usually occurs at the rearmost screw holes nearest the free ends of the clamping frame. For a rear toe binding, failure also usually occurs at the rearmost screw holes nearest the foot.
The foregoing problem is aggravated by the current practice of making the binding rubber from a plastic material rather than latex. When formulated to have the same elongation as natural rubber, plastic binding rubbers are not as strong as natural rubber and therefore are more likely to fail. If formulated to have the same tensile strength as natural rubber, on the other hand, plastic binding rubbers do not have as much stretch or elongation as natural rubber and therefore are less comfortable and more difficult to fit around the skier's foot.